However, the regulator said the spike of 60 per cent rise was a 'worst-case scenario', which the UK could avoid by meeting renewable and carbon targets and invests in nuclear energy, the commission said.

The report also warned that £200 billion was needed to meet carbon emissions targets, build new power stations and secure future energy supplies.

The news comes shortly after the energy supplier E.ON announced it was postponing its planned new 'clean' coal facility at Kingsnorth.

However, environmentalists have said that the Kingsnorth power plant would have meant an investment in damaging polluting technology and was the wrong investment for a sustainable future for Britain.

Friends of the Earth's director Andy Atkins said: "We should be investing in clean energy sources not building new dirty coal-fired power stations."

However, there was a silver lining in an otherwise cloudy report, as Ofgem confirmed that emissions were likely to fall by up to 43 per cent from 2005 levels.

The report outlines four possible scenarios. The other scenarios would see prices rise to a more moderate, 14 to 25 per cent above inflation by 2020 - which is still likely to be of concern to most consumers.